A randomized comparison of ovulation induction and hormone profile between the aromatase inhibitor anastrozole and clomiphene citrate in women with infertility.

Background: IN the present study we evaluated and compared the effects of ovulation and hormonal dynamics induced by anastrozole and clomiphene citrate in women with infertility.

Materials And Methods: Thirty-three infertile patients, aged 25-41 years, were enrolled. Patients received either anastrozole 1 mg daily (AI group) or clomiphene citrate 100 mg daily (CC group) from cycle day 3 to day 7. Number of mature follicles (> or =18 mm), endometrial thickness, pregnancy rate and serial hormone profiles (follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E(2)), testosterone and progesterone) were measured on cycle day 3, day 8, day 10, the day of intrauterine insemination (IUI), day 7 after IUI and day 14 after IUI.

Results: Baseline parameters were similar in the two groups, including age, body mass index, infertility duration and day-3 serum hormones except FSH. The mean FSH value on day 3 was significantly different (4.3 mIU/ml in the AI group vs. 6.3 mIU/ml in the CC group; p < 0.05). The women receiving anastrozole had fewer ovulatory follicles (1.2 in the AI group vs. 1.8 in the CC group; p < 0.05) and a thicker endometrium (10.6 mm in the AI group vs. 7.8 mm in the CC group; p < 0.05). The levels of progesterone and testosterone were similar during ovulation stimulation cycles in both groups. On the other hand, the AI group had a significantly higher LH level but a significantly lower E(2) level in the stimulation cycle.

Conclusion: Anastrozole has a high pregnancy rate, although it induces fewer ovulatory follicles compared with clomiphene citrate. The two drugs gave different responses of FSH, LH and E2 during stimulation cycles.